“The older you get, the better you get. Unless you’re a banana”

“Aging like fine wine” is a saying meaning that someone/something is getting better with age. Bananas spoil very quickly. “Aging like a fine banana” means that someone/something is not aging well at all.
 
“He’s aging like a fine banana wine” was posted on the newsgroup alt.fan.howard-stern on June 12, 2002. “‘Man you girl is aging like a Banana’ - Darrel’” was posted on Twitter by Shawnie F. Baby on March 26, 2011. “I think I’m aging like a fine wine…I think you are aging like a banana…” was posted on Twitter by Mae Ann on August 8, 2011. “I’m aging like a fine banana” was posted on Twitter by Mark Peters on December 10, 2011.
 
“The older you get, the better you get. Unless you’re a banana” is a saying that has been printed on many images. On the American television sitcom The Golden Girls, the episode “And Then There Was One” that originally aired on January 31, 1987, the character Rose Nylund (played by Betty White) said:
   
“My mother always used to say, ‘The older you get, the better you get. Unless you’re a banana.’”
   
     
IMDb (The Internet Movie Database)   
The Golden Girls (1985–1992)
And Then There Was One
TV-PG | 30min | Comedy, Drama | Episode aired 31 January 1987
Season 2 | Episode 16

The girls believe that an infant entrusted to their care by a couple during a marathon has been abandoned.
Director: Terry Hughes
Writers: Susan Harris (created by), Russell Marcus
 
Springfield! Springfield!
The Golden Girls (1985) s02e16
Episode Script
And Then There Was One

(...)
My mother always used to say, “The older you get, the better you get. Unless you’re a banana.”
 
Google Books
The Quotable Quote Book
By Merrit Malloy and Shauna Sorensen
New York, NY: Carol Pub. Group
1990
Pg. 15:
My Mother always used to say: “The older you get, the better you get — unless you’re a banana.”
Rose Nylund, “The Golden Girls”
       
Google Groups: alt.fan.howard-stern
I Get Greatly Disturbed When…very long reply
miNor salaZaar
6/12/02
(...)
The only guy on the show who’s getting better is Booey; he’s aging like a fine banana wine.
   
Twitter
Shawnie F. Baby
@Shawnie_Boy
“Man you girl is aging like a Banana” - Darrel
1:04 PM · Mar 26, 2011·erased734497
   
Twitter
Shawnie F. Baby
@Shawnie_Boy
“Yo son.. Your girl is aging like a Banana…” *Dayrel voice*
8:25 PM · May 8, 2011·erased734497
   
Twitter
the daughter of a madam inside of a pink phantom
@mahaliahayana
jasmine guy is aging like a banana. geez louise.
12:36 PM · Jun 17, 2011·Twitter Web Client
   
Twitter
Mae Ann
@Maeyoung14
I think I’m aging like a fine wine…I think you are aging like a banana…
5:06 PM · Aug 8, 2011·Twitter for iPhone
   
Twitter
Big Gay Ice Cream
@biggayicecream
I’m aging like a banana. More spots every day, but getting sweeter inside. Be warned, though: one day I’ll suddenly be rotted mush.
5:10 PM · Aug 22, 2011·Echofon
 
Twitter 
Mark Peters
@wordlust
I’m aging like a fine banana.
12:06 AM · Dec 10, 2011·Twitter Web Client
   
Twitter
Mark Peters
@wordlust
I’m aging like a fine banana.
9:21 PM · Jul 10, 2012·Twitter Web Client
 
Twitter
Dumb Beezie
@dumbbeezie
I’m aging like a fine banana
7:20 PM · Jun 14, 2018·Twitter for iPhone
     
Google Books
Title The Older You Get The Better You Get Unless You Are A… Banana: Blank Lined Notebook ( Bananas ) Palms
Author Tropical Designs T
Publisher Independently Published, 2019
ISBN 1080178716, 9781080178711
Length 122 pages
 
Screen Rant
10 Golden Girls Memes That Are Too Hilarious For Words
BY KAYLEENA PIERCE-BOHEN – ON JUL 13, 2019 IN LISTS
(...)
10 AGING LIKE A BANANA
THE OLDER YOU GET, THE BETTER YOU GET. UNLESS YOU’RE A BANANA.
Rose may not have the wit of Dorothy or the candor of Blanche, but she has her own particular brand of wisdom. She often uses anecdotes from her hometown of St. Olaf to illustrate life lessons, and, while her quaint stories may seem hokey to some, they often do shed some sort of quirky light on problems involving the other girls.
 
Dorothy often makes fun of Rose for being “simple”,”, but that doesn’t mean her simplistic observations don’t have merit. Getting old doesn’t have to mean stopping pursuits you had when you were young, and it doesn’t mean you’ve outlived your usefulness. While getting old may mean bad news for a banana, it can still be used for banana bread.